Drivers/Net/MarvellYukon: Don't re-use DMA buffers

Change the receive buffers to be single-use only. This involves a few
changes that work together:
1. Change msk_newbuf() to not attempt to re-use or free a buffer,
2. Change msk_rxeof() free the buffer when it is done with it,
3. Store a temporary copy of the received data for passing to
   the Receive Queue,
4. Call the required Flush() and Unmap() on the DMA buffer.

In addition this means failure to allocate a new buffer is a failure
of msk_rxeof().

Note that this change makes the driver work the way the FreeBSD driver
(from which this driver was derived) works, and this simply removes an
optimization (the code in msk_newbuf() which re-uses the buffers. This
removal of the optimization is done for two reasons:
1. The optimization failed to work for 64-bit DMA transfers;
2. The UEFI specification, version 2.6, section 13.4 requires calls to
   Flush() and Unmap() before reading a DMA write buffer from the CPU,
   which doesn't fit with the optimization as it existed.

Reverting back to the behavior as it was in the FreeBSD driver solves
number 1 and 2 above, and makes this driver more consistent with
something we know to be working. There is slightly more overhead, but
it is more consistent with the UEFI standard.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Alan Ott <alan@softiron.co.uk>
[ardb: replaced struct assignment with gBS->CopyMem()]
Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>

1 files changed, 22 insertions, 11 deletions

diff --git a/Drivers/Net/MarvellYukonDxe/if_msk.c b/Drivers/Net/MarvellYukonDxe/if_msk.c
index d2102dc..2b505c3 100644
--- a/Drivers/Net/MarvellYukonDxe/if_msk.c
+++ b/Drivers/Net/MarvellYukonDxe/if_msk.c
@@ -581,13 +581,6 @@ msk_newbuf (
 

   rxd = &sc_if->msk_cdata.msk_rxdesc[idx];

 

-  if ((rxd->rx_m.Buf != NULL) && (rxd->rx_m.Length >= Length)) {

-    return EFI_ALREADY_STARTED;

-  } else if (rxd->rx_m.Buf != NULL) {

-    mPciIo->Unmap (mPciIo, rxd->rx_m.DmaMapping);

-    mPciIo->FreeBuffer (mPciIo, EFI_SIZE_TO_PAGES (rxd->rx_m.Length), rxd->rx_m.Buf);

-  }

-

   Status = mPciIo->AllocateBuffer (mPciIo, AllocateAnyPages, EfiBootServicesData, EFI_SIZE_TO_PAGES (Length), &Buffer, 0);

   if (EFI_ERROR (Status)) {

     return Status;

@@ -1848,6 +1841,7 @@ msk_rxeof (
   struct msk_rxdesc   *rxd;

   INTN                cons;

   INTN                rxlen;

+  MSK_DMA_BUF         m;

 

   DEBUG ((EFI_D_NET, "Marvell Yukon: rxeof\n"));

 

@@ -1871,26 +1865,41 @@ msk_rxeof (
       break;

     }

 

+    rxd = &sc_if->msk_cdata.msk_rxdesc[cons];

+

+    gBS->CopyMem (&m, &rxd->rx_m, sizeof(m));

+

     Status = msk_newbuf (sc_if, cons);

     if (EFI_ERROR (Status)) {

+      // This is a dropped packet, but we aren't counting drops

       // Reuse old buffer

       msk_discard_rxbuf (sc_if, cons);

+      break;

+    }

+

+    Status = mPciIo->Flush (mPciIo);

+    if (EFI_ERROR (Status)) {

+      DEBUG ((EFI_D_NET, "Marvell Yukon: failed to Flush DMA\n"));

+    }

+

+    Status = mPciIo->Unmap (mPciIo, rxd->rx_m.DmaMapping);

+    if (EFI_ERROR (Status)) {

+      DEBUG ((EFI_D_NET, "Marvell Yukon: failed to Unmap DMA\n"));

     }

+

     Status = gBS->AllocatePool (EfiBootServicesData,

                                 sizeof (MSK_LINKED_DMA_BUF),

                                 (VOID**) &m_link);

     if (!EFI_ERROR (Status)) {

       gBS->SetMem (m_link, sizeof (MSK_LINKED_DMA_BUF), 0);

-      rxd = &sc_if->msk_cdata.msk_rxdesc[cons];

-

       m_link->Signature = RX_MBUF_SIGNATURE;

       Status = gBS->AllocatePool (EfiBootServicesData,

                                   len,

                                   (VOID**) &m_link->DmaBuf.Buf);

       if(!EFI_ERROR (Status)) {

-        gBS->CopyMem (m_link->DmaBuf.Buf, rxd->rx_m.Buf, len);

+        gBS->CopyMem (m_link->DmaBuf.Buf, m.Buf, len);

         m_link->DmaBuf.Length = len;

-        m_link->DmaBuf.DmaMapping = rxd->rx_m.DmaMapping;

+        m_link->DmaBuf.DmaMapping = NULL;

 

         InsertTailList (&mSoftc->ReceiveQueueHead, &m_link->Link);

       } else {

@@ -1899,6 +1908,8 @@ msk_rxeof (
     } else {

       DEBUG ((EFI_D_NET, "Marvell Yukon: failed to allocate receive buffer link. Dropping Frame\n"));

     }

+

+    mPciIo->FreeBuffer (mPciIo, EFI_SIZE_TO_PAGES (m.Length), m.Buf);

   } while (0);

 

   MSK_INC (sc_if->msk_cdata.msk_rx_cons, MSK_RX_RING_CNT);